1. Field of the Invention
This invention relates to an escalator with a high speed inclined section in which the steps move faster in the intermediate inclined section than in the upper and lower landing sections.
2. Description of the Related Art
Nowadays, a large number of escalators of great height are installed in subway stations or the like. In an escalator of this type, the passenger is obliged to stand on a step for a long period of time, which is often rather uncomfortable. In view of this, a high-speed escalator has been developed. However, in such a high-speed escalator, there is a limitation regarding the traveling speed from the viewpoint of allowing the passengers to get off and on safely.
In view of this, there has been proposed an escalator with a high speed inclined section in which the steps move faster in the intermediate inclined section than in the upper and lower landing sections, whereby it is possible to shorten the traveling time for the passenger. An example of an escalator with a high speed inclined section is disclosed in Japanese Patent Application Laid-Open No. Sho 51-116586.
FIG. 5 is a schematic side view of an example of a conventional escalator with a high speed inclined section. In the drawing, a main frame 1 is provided with a plurality of steps 2 connected together in an endless fashion. The steps 2 are driven by a drive unit 3 to be circulated. The main frame 1 is provided with a pair of main tracks 4 forming a loop track for the steps 2, a pair of trailing tracks 5 for controlling the attitude of the steps 2, and a pair of auxiliary tracks 6 for varying the gap between adjacent steps 2.
The loop track for the steps 2 formed by the main tracks 4 have a forward track section, a return track section, an upper reversing section F, and a lower reversing section I. The forward track section of the loop track includes a horizontal upper landing section (upper horizontal section) A, an upper curved section B, an intermediate inclined section (fixed inclination section) C of a fixed inclination angle, a lower curved section D, a horizontal lower landing section (lower horizontal section) E, an upper transition section G, and a lower transition section H.
The intermediate inclined section C is situated between the upper landing section A and the lower landing section E. The upper curved section B is situated between the upper landing section A and the intermediate inclined section C. The lower curved section D is situated between the lower landing section E and the intermediate inclined section C. The upper transition section G is situated between the upper landing section A and the upper reversing section F. The lower transition section H is situated between the lower landing section E and the lower reversing section I.
Above the steps 2 of the upper and lower landing sections A and E, there are arranged a pair of landing plates 22a and 22b. The landing plates 22a and 22b are arranged in the floor portions of the upper and lower landing sections A and E so as to cover the steps 2. Arranged upright above the main frame 1 are a pair of moving handrail devices 23. The moving handrail devices 23 are arranged on either side of the steps 2 with respect to the width direction thereof.
FIG. 6 is a side view showing the portion around the upper landing section A of FIG. 5. Each step 2 has a tread 7 for carrying a passenger, a riser 8 formed by bending the lower end portion of the tread 7, a step link roller shaft 9, a pair of step link rollers 10 rotatable around the step link roller shaft 9, a trailing roller shaft 11, and a pair of trailing rollers 12 rotatable around the trailing roller shaft 11. The step link rollers 10 roll on the main tracks 4. The trailing rollers 12 roll on the trailing tracks 5.
The step link roller shafts 9 of adjacent steps 2 are connected to each other by a pair of link mechanisms (bending links) 13. Each link mechanism 13 has first through fifth links 14 through 18.
One end portion of the first link 14 is rotatably connected to the step link roller shaft 9. The other end portion of the first link 14 is rotatably connected to the middle portion of the third link 16 through a shaft 19. One end portion of the second link 15 is rotatably connected to the step link roller shaft 9 of the adjacent step 2. The other end portion of the second link 15 is rotatably connected to the middle portion of the third link 16 through the shaft 19.
One end portion of the fourth link 17 is rotatably connected to the middle portion of the first link 14. One end portion of the fifth link 18 is rotatably connected to the middle portion of the second link 15. The other end portions of the fourth and fifth links 17 and 18 are connected to one end portion of the third link 16 through a slide shaft 20.
Provided in one end portion of the third link 16 is a guide groove 16a for guiding the sliding of the slide shaft 20 in the longitudinal direction of the third link 16. Provided at the other end of the third link 16 is a rotatable auxiliary roller 21. The auxiliary roller 21 is guided by the auxiliary track 6.
When the auxiliary roller 21 is guided by the auxiliary track 6, the shape of the link mechanism 13 is changed and extends and retracts, and the distance between the step link roller shafts 9, that is, the distance between the adjacent steps 2, is varied. In other words, the line of the auxiliary track 6 is designed so that the distance between the adjacent steps 2 varies.
Next, the operation of this conventional escalator will be described. The speed of the steps 2 is varied by varying the distance between the step link roller shafts 9 of the adjacent steps 2. That is, the distance between the step link roller shafts 9 is larger in the intermediate inclined section C than in the upper and lower landing sections A and E where passengers get on or off, whereby the steps 2 move faster in the intermediate inclined section C than in the upper and lower landing sections A and E.
The first, second, fourth, and fifth links 14, 15, 17, and 18 form a so-called pantograph type quadruple link mechanism, and the angle made by the first and second links 14 and 15, with the third link 16 being an axis of symmetry, can be increased or decreased, whereby it is possible to vary the distance between the step link roller shafts 9 connected to the first and second links 14 and 15.
That is, when the distance between the main track 4 and the auxiliary track 6 is diminished, the link mechanism 13 operates like the framework of an umbrella when it is opened, and the distance between the step link roller shafts 9 of the adjacent steps 2 increases.
In the intermediate inclined section C shown in FIG. 5, the distance between the main track 4 and the auxiliary track 6 is minimum, and the distance between the step link roller shafts 9 of the adjacent steps 2 is maximum. Thus, the speed of the steps 2 is maximum. In this condition, the first and second links 14 and 15 are arranged substantially in a straight line.
Further, in the escalator with a high speed inclined section in which the distance between the steps 2 increases in the intermediate inclined section C, the riser 8 downwardly protrudes so as to fill the opening between the adjacent treads 7. When reversing the steps 2 having the risers 8 of this configuration in the reversing sections F and I, the steps 2 will interfere with each other, unless the distance between the steps 2 is increased. Thus, in the reversing sections F and I, the distance between the steps 2 is increased. Accordingly, in the transition sections G and H, an operation to expand the link mechanism 13 is conducted.
However, in the conventional escalator with a high speed inclined section constructed as described above, it is necessary to provide a large number of bearing portions in the link mechanism 13, and the influence of play due to production errors, wear, etc. of the bearing portions is great, so that there is a danger of the distance between the step link roller shafts 9 becoming too large or, conversely, the adjacent steps 2 interfering with each other.
Further, in the conventional escalator with a high speed inclined section, when the operation to expand the link mechanism 13 is conducted in the transition sections G and H, the third link 16 protrudes beyond the height of the landing plates 22a and 22b. Thus, in an area where the moving handrail device 23 is directly above the link mechanism 13, it is impossible to perform the operation to expand the link mechanism 13. Thus, as shown, for example, in FIG. 7, the distance between the steps 2 starts to increase at a position well on the inner side rather than at an end portion 22c of the landing plate 22a and 22b. As a result, the length of the upper landing section A and that of the lower landing section E become rather large, so that the size of the escalator is rather large.
Further, in the conventional escalator with a high speed inclined section, the auxiliary track 6 exhibits a smooth arcuate configuration in the upper curved section B and the lower curved section D. Thus, the change in the difference in height between the adjacent steps 2 is not completed in the upper curved section B and the lower curved section D, and the change in the difference in height continues in the upper landing section A, the lower landing section E, or the intermediate inclined section C. Thus, as shown, for example, in FIG. 8, the sectional configuration of the riser 8 is discontinuous and bent in the direction of inclination of the intermediate inclined section C; it cannot be formed in a continuous plane or curve, resulting in an increase in production costs.